The present invention relates to a trench structure semiconductor device and a method for producing it. The present invention relates, in particular, inter alia, also to a YFET field plate trench transistor with potential-free or floating field plates or field electrode devices and improved electrical coupling between the field plates or field electrode devices.
In the further development of modern semiconductor technologies, trench structure semiconductor devices or components with a trench structure are also increasingly being used. The trench structures or trenches provided in a semiconductor material region in this case may contain main electrode devices or control electrode devices. Furthermore or as an alternative thereto, it is also conceivable for field plates or field electrode devices also to be provided in the respective trench structures or trenches. The field plates or field electrode devices, even if they are formed such that they are spatially at a distance and electrically insulated from the wall regions or bottom regions of the trench structure by corresponding insulation regions, can electrically influence the surroundings there in the adjoining semiconductor material region adjacent to the trench structure and can improve the charge depletion in the off-state case. In this way, by providing corresponding field plates or field electrode devices, a specific characteristic can be impressed or modulated on corresponding semiconductor devices or components and, for a predetermined breakdown strength, the doping of the drift path can be increased and the on resistance can thereby be significantly reduced.
What is of crucial importance in the mode of operation of the field plates or field electrode devices is the coupling to the surrounding semiconductor material region, but also the coupling to the further electrode devices, e.g., control electrodes or main electrodes, but indeed also often the electrical coupling of a given field plate or field electrode device to the further field plates or field electrode devices. In this case, coupling means that e.g., as a result of the capacitance between field plate and semiconductor, the voltages of the field plate change with the voltage of the semiconductor material region, and vice versa.
For these and other reasons, there is a need for the present invention.